diff options
| author | Eric Blake <eblake@redhat.com> | 2016-06-23 16:37:07 -0600 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-07-05 16:46:24 +0200 |
| commit | 82524274eada16bfa2a263cbdbcae0fe948ed040 (patch) | |
| tree | 924adc077bf00ed689f393b983d5fba83e5e9498 | |
| parent | a604fa2ba55f645abbb082469ed595f58f657ac8 (diff) | |
block: Fix harmless off-by-one in bdrv_aligned_preadv()
If the amount of data to read ends exactly on the total size
of the bs, then we were wasting time creating a local qiov
to read the data in preparation for what would normally be
appending zeroes beyond the end, even though this corner case
has nothing further to do.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/io.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/io.c b/block/io.c index 994d3fafbf..82c9ff0a04 100644 --- a/block/io.c +++ b/block/io.c @@ -1036,7 +1036,7 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, } max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align); - if (bytes < max_bytes) { + if (bytes <= max_bytes) { ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0); } else if (max_bytes > 0) { QEMUIOVector local_qiov; |